P: live captions that follow their source's metadata

Co-Authored-By: Claude Opus 5.5 <[email protected]>

ROADMAP.md

@@ -109,6 +109,7 @@ DesignCraft aims at full Adobe InDesign parity — and to be better: faster, ope
 - Effects: Inner Glow (edge or centre), Bevel and Emboss (inner bevel lit from the light angle), Satin (`object.innerGlow`, `object.bevel`, `object.satin`); PDF export now keeps soft effects: objects with shadows, glows, feathers, bevels or satin go out as 300 ppi transparent images of their appearance (threaded text frames excepted).
 - Directional Feather (`object.directionalFeather {widths: [top, left, bottom, right]}`): each side fades over its own width.
 - View ▸ Flattener Preview (`view.flattenerPreview`): objects involving transparency highlighted in red; knockout groups export as images (PDF output has no knockout groups).
+- Live captions (`object.caption {live: true}`, Object ▸ Captions ▸ Generate Live Caption): the caption text is re-filled from the source object's metadata after every edit (same undo step).
 - Drag and drop text editing: drag selected text to move it (Alt copies) with its formatting (`text.release`).
 - Image Import Options: place any page of a multi-page PDF (`file.place {pdfPage}`; the app asks which page), shown on screen and embedded as that page in PDF export.
 - Define Lists: named numbered lists that continue across stories in page order (`list.define`, paragraph `listName` / `startAt`), round-tripped through IDML; `null` in `type.para` / `type.char` now removes an override.

crates/doc/src/item.rs

@@ -467,6 +467,14 @@ pub struct ObjectLiquid {
     pub pin_right: bool,
 }
 
+/// The source and template of a live caption.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct LiveCaption {
+    pub source: ItemId,
+    pub template: String,
+}
+
 /// Media panel options for a placed video or sound.
 #[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase", default)]
@@ -908,6 +916,10 @@ pub struct Item {
     /// Liquid Layout (object-based pages): pins and resize permissions.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub liquid: Option<ObjectLiquid>,
+    /// Live caption: this text frame shows `template` filled from the source object's metadata,
+    /// kept current as the source changes.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub live_caption: Option<LiveCaption>,
     /// Object › Object Layer Options: layers of a placed PDF that are hidden.
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub pdf_hidden_layers: Vec<String>,
@@ -967,6 +979,7 @@ impl Item {
             xml_tag: String::new(),
             button: None,
             pdf_hidden_layers: Vec::new(),
+            live_caption: None,
             media: None,
             liquid: None,
             states: Vec::new(),

crates/engine/src/cmd/captions.rs

@@ -14,7 +14,7 @@ pub fn specs() -> Vec<CommandSpec> {
         "Generate Static Caption",
         ["Object", "Captions"],
         None,
-        "{text?: template (default \"{name}\"; variables {name} {path} {altText} {label} {ppi} {dimensions} {format}), position?: below|above|left|right, offset? (pt, 0), height? (pt, 24), style?: paragraph style, ids?} → {ids}",
+        "{text?: template (default \"{name}\"; variables {name} {path} {altText} {label} {ppi} {dimensions} {format}), position?: below|above|left|right, offset? (pt, 0), height? (pt, 24), style?: paragraph style, live?: bool (kept current as the source changes), ids?} → {ids}",
         has_selection,
         caption
     )]
@@ -44,7 +44,7 @@ fn variable(d: &Document, it: &Item, xf: designcraft_geom::Affine, name: &str) -
     }
 }
 
-fn fill(d: &Document, it: &Item, xf: designcraft_geom::Affine, template: &str) -> String {
+pub(crate) fn fill(d: &Document, it: &Item, xf: designcraft_geom::Affine, template: &str) -> String {
     let mut out = String::new();
     let mut rest = template;
     while let Some(i) = rest.find('{') {
@@ -75,6 +75,7 @@ fn caption(s: &mut Session, p: &Value) -> Result<Value> {
     let offset = p.get("offset").and_then(Value::as_f64).unwrap_or(0.0);
     let height = p.get("height").and_then(Value::as_f64).unwrap_or(24.0).max(1.0);
     let style = str_param(p, "style").map(str::to_string);
+    let live = p.get("live").and_then(Value::as_bool).unwrap_or(false);
     if let Some(st) = &style
         && s.doc()?.doc.styles.para(st).is_none()
     {
@@ -96,7 +97,11 @@ fn caption(s: &mut Session, p: &Value) -> Result<Value> {
                 _ => Rect::new(b.x0, b.y1 + offset, b.x1, b.y1 + offset + height),
             };
             let para = ParaFormat { style: style.clone().unwrap_or_else(|| d.styles.default_paragraph.clone()), ..Default::default() };
+            let source = *id;
             let (cid, _) = d.add_text_frame(loc.spread, r, lid, &text, para)?;
+            if live && let Some(c) = d.item_mut(cid) {
+                c.live_caption = Some(designcraft_doc::LiveCaption { source, template: template.clone() });
+            }
             made.push(cid);
         }
         if made.is_empty() {
@@ -107,6 +112,29 @@ fn caption(s: &mut Session, p: &Value) -> Result<Value> {
     })
 }
 
+/// Bring live captions up to date with their source objects (the text frame's story is
+/// replaced when its text changed; a caption whose source is gone keeps its last text).
+pub(crate) fn refresh_live(d: &mut Document) -> bool {
+    let mut todo = Vec::new();
+    for id in d.all_items() {
+        let Some(c) = d.item(id) else { continue };
+        let (Some(lc), Some(tf)) = (&c.live_caption, c.text_frame()) else { continue };
+        let (Some(loc), Some(src)) = (d.find(lc.source), d.item(lc.source)) else { continue };
+        let text = fill(d, src, d.parent_xf(&loc) * src.xf, &lc.template);
+        if d.story(tf.story).is_some_and(|st| st.text != text) {
+            todo.push((tf.story, text));
+        }
+    }
+    let changed = !todo.is_empty();
+    for (sid, text) in todo {
+        if let Some(st) = d.story_mut(sid) {
+            let len = st.len();
+            st.replace(0..len, &text);
+        }
+    }
+    changed
+}
+
 #[cfg(test)]
 mod tests {
     use serde_json::json;
@@ -130,4 +158,23 @@ mod tests {
         assert_eq!(d.stories[&sid].text, "Figure fig-1: Harbour at dawn");
         assert!(s.execute("object.caption", &json!({"ids": [a], "position": "sideways"})).is_err());
     }
+
+    #[test]
+    fn live_caption_follows_its_source() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({})).unwrap();
+        let a = s.execute("frame.create", &json!({"rect": [72, 72, 272, 172]})).unwrap()["id"].as_u64().unwrap();
+        s.execute("object.altText", &json!({"text": "First", "ids": [a]})).unwrap();
+        let r = s.execute("object.caption", &json!({"ids": [a], "text": "Photo: {altText}", "live": true})).unwrap();
+        let cid = designcraft_doc::ItemId(r["ids"][0].as_u64().unwrap());
+        let text = |s: &Session| {
+            let d = &s.doc().unwrap().doc;
+            d.stories[&d.item(cid).unwrap().text_frame().unwrap().story].text.clone()
+        };
+        assert_eq!(text(&s), "Photo: First");
+        s.execute("object.altText", &json!({"text": "Second", "ids": [a]})).unwrap();
+        assert_eq!(text(&s), "Photo: Second", "updated with the source");
+        s.execute("edit.undo", &json!({})).unwrap();
+        assert_eq!(text(&s), "Photo: First", "one undo step for both");
+    }
 }

crates/engine/src/cmd/mod.rs

@@ -5,7 +5,7 @@ pub mod anchors;
 mod articles;
 pub mod book;
 mod buttons;
-mod captions;
+pub(crate) mod captions;
 mod changes;
 mod colorsettings;
 mod conditions;

crates/engine/src/lib.rs

@@ -348,6 +348,17 @@ impl Session {
         if self.prefs.smart_text_reflow && spec.undoable {
             self.smart_reflow();
         }
+        // Live captions follow their sources.
+        if spec.undoable
+            && let Some(st) = self.active_mut()
+            && st.interaction.is_none()
+            && st.doc.spreads.iter().any(|sp| sp.items.iter().any(|i| i.live_caption.is_some()))
+        {
+            let mut d = (*st.doc).clone();
+            if cmd::captions::refresh_live(&mut d) {
+                st.doc = Arc::new(d);
+            }
+        }
         // Record undo if the document changed (and we're not previewing an interaction).
         if let (Some((uid, old)), Some(st)) = (before, self.active_mut())
             && st.uid == uid

crates/ui-egui/src/menus.rs

@@ -483,6 +483,7 @@ pub const MENUS: &[(&str, &[&str])] = &[
             "<",
             ">Captions",
             "cmd:object.caption",
+            "cmd:object.caption|Generate Live Caption|{\"live\": true}",
             "<",
             ">Anchored Object",
             "cmd:anchored.options",

docs/parity.md

@@ -11,7 +11,7 @@ Each row of the InDesign feature catalogue is scored **D** (done), **P** (partia
 |---|---|---|---|---|---|
 | P0 | 102 | 100 | 2 | 0 | 99% |
 | P1 | 97 | 94 | 3 | 0 | 98% |
-| P2 | 76 | 51 | 25 | 0 | 84% |
+| P2 | 76 | 53 | 23 | 0 | 85% |
 
 | Area | Parity |
 |---|---|
@@ -22,12 +22,12 @@ Each row of the InDesign feature catalogue is scored **D** (done), **P** (partia
 | Transform | 100% |
 | Fill, stroke, colour | 99% |
 | Effects & transparency | 92% |
-| Placing & links | 91% |
+| Placing & links | 93% |
 | Type & text frames | 99% |
 | Typography | 98% |
 | Styles | 97% |
 | Tables | 98% |
-| Long documents | 96% |
+| Long documents | 100% |
 | Interactivity & digital | 90% |
 | Output & production | 82% |
 | XML & automation | 83% |
@@ -176,7 +176,7 @@ Open P0 items: Vector/page formats (PDF/AI/SVG/EPS place), Export to PDF (print)
 | Placing & links | Effective/actual PPI | P0 | D |
 | Placing & links | Relink to folder / extension | P1 | D |
 | Placing & links | Copy Links To / Package | P1 | D |
-| Placing & links | Captions | P2 | P |
+| Placing & links | Captions | P2 | D |
 | Placing & links | Image import options | P1 | D |
 | Placing & links | Linked text/stories | P2 | D |
 | Placing & links | Display performance | P0 | D |
@@ -267,7 +267,7 @@ Open P0 items: Vector/page formats (PDF/AI/SVG/EPS place), Export to PDF (print)
 | Long documents | Cross-references | P2 | D |
 | Long documents | Running headers via variables | P1 | D |
 | Long documents | Footnotes/endnotes | P1 | D |
-| Long documents | Captions | P2 | P |
+| Long documents | Captions | P2 | D |
 | Interactivity & digital | Hyperlinks panel | P1 | D |
 | Interactivity & digital | Bookmarks | P1 | D |
 | Interactivity & digital | Buttons and Forms | P2 | P |